This invention pertains to line of sight aligning devices for use with optical instruments having viewing openings requiring precise alignment with the line of sight of the viewer.
In the field of optics, there are many optical instruments which require for their proper and accurate use precise alignment of the line of sight of the viewer with a viewing opening in the instrument. This is the case, for example, in Hill U.S. Pat. Nos. 4,109,237 and 493,366 both of which pertain to apparatus and method for identifying individuals through their retinal vasculature patterns. The apparatus employed directs a beam of light into the eye of the subject and reads the retinal vasculature pattern from the reflected light. The resulting information then is used for identification of the subject.
In this sequence, it is imperative that the line of sight of the subject be located precisely with respect to the analyzing instrument in order to obtain reproduceable results.
Without mechanical assistance, precise location inherently is difficult of achievement. It is difficult for a viewer, unassisted, to align his eye precisely with the viewing opening of an instrument. The problem is complicated by the reluctance of the viewer for sanitary reasons to place his eye in direct contact with an eye piece. Such contact is further undesirable since female viewers smear mascara and eyeshadow over the contacted portion of the eyepiece.
It accordingly is the general purpose of the present invention to provide a line of sight aligning device for use with optical instruments having viewing openings requiring precise 10 alignment of the line of sight of the viewer.
It is a further object of the present invention to provide a line of sight aligning device which is simple, easy to use, usable in conjunction with a wide variety of optical instruments, and accurate.
A further object of the present invention is the provision of line of sight aligning apparatus which achieves its purpose without requiring contact of the eye of the viewer with an eyepiece.
The foregoing and other objects of this invention are achieved by the provision of a line of sight aligning device for use with optical instruments having a viewing opening, which device comprises a body member having an eye opening and a nose recess in operative position relative to each other. Positioning means position the body member relative to the optical instrument with its eye opening in operative position relative to the viewing opening of the optical instrument. A straight edge is positioned on the front face of the body member above the eye opening and the recess, but within the field of vision of the viewer. The straight edge is disposed substantially at right angles to the longitudinal axis of the nose recessed in the body member.
A pad adapted to serve as a head rest is mounted on the front face of the body member. It preferably is integral with the straight edge.
By inserting his nose in the nose recess, looking into the eye opening, and simultaneously positioning his head in such a position that the longitudinal axis of his nose intersects the straight edge at right angles, precise alignment of his line of sight with whatever instrument is associated with the device is assured.